Hayley C. Norman

This study assessed the feasibility of using faecal near infrared reflectance spectroscopy (NIRS) to predict enteric methane production and yield, dry matter and nutrient intake, and the nutritional value of diets offered to cattle. The faecal samples (n=219) were generated in three historical grass–legume forage experiments that were designed to quantify antimethanogenic potential of forages. This work leveraged the dried faecal samples as they were from animals (n=46), each offered a range of treatment diets with measured feed and nutrient intake as well as methane emissions. Emissions for each animal per diet were measured in open‑circuit respiration chambers over two consecutive 23 h periods. Diet quality was determined by chemical analysis of dietary components. NIRS calibrations were developed using partial least squares methods with 78% of samples across the experiments, with the remainder (49 samples originating form 3 randomly selected animals per experiment) reserved for independent validation. We found that faecal NIRS methods could predict measured methane production, with a relative prediction deviation (RPD) of 2.3 and a standard error of prediction of 11.7 g day⁻¹. To our knowledge, this represents the first direct prediction of methane emissions using faecal NIRS. Strong predictions were obtained for individual metabolizable energy intake (RPD 2.1), crude protein intake (RPD 2.5), dry matter intake (RPD 1.8), and diet composition (legume to grass ratio; RPD 4.2). Diet quality traits such dry matter digestibility, crude protein, acid detergent fibre, neutral detergent fibre and ash, were also predicted with high accuracy (RPD 2.2-4.7). These findings demonstrate that faecal NIRS offers a rapid, low‑cost approach for estimating individual animal traits that are otherwise technically difficult and expensive to measure. The technique has potential to support grazing management decisions aimed at improving productivity and environmental sustainability, to assist in validation of methane mitigation strategies, and to support large‑scale phenotyping of individuals for intake, quality of the diet selected and methane production in genetic improvement programmes. Further work is required to test relevance across a broader range of production systems, expand the calibrations, streamline sample processing and potentially evaluate the performance of portable spectrometers for in-field application. With expansion and refinement using more faecal samples with data generated open‑circuit respiration chambers, faecal NIRS could become a significant technology to enable improved productivity, sustainable grazing management and emissions quantification in ruminant livestock grazing systems.

Herbivores contribute significantly to seed dispersal in both natural and agricultural systems through endozoochory, a process that can break seed physical dormancy ( PY ) in leguminous plants. However, the detailed mechanisms governing germination following seed ingestion and the combined effects of digestion and environmental conditions remain poorly understood, particularly in Mediterranean climates. This study examined the effect of sheep ingestion on PY break and germination potential in four pasture legume species critical for grassland sustainability. Seed from two species ( Medicago polymorpha and Ornithopus sativus ) were fed to sheep inside intact ligneous pods, another in a linear membranous pod ( Biserrula pelecinus ) and the last in membranous pods arranged in a capitulum ( Trifolium hirtum ), mimicking consumption in nature. Viable seeds recovered from faecal pellets and non‐ingested (control) seeds were subsequently placed under natural soil conditions for 111 days, during which seed mass, moisture content, and PY status were periodically assessed. Seeds that had passed through the digestive tract showed significant increases in mass and moisture content after ingestion, indicating partial hydration post ingestion. The proportion of PY seeds decreased in all species after being placed on the soil surface, but the rate of dormancy loss varied among species. Seeds ingested within ligneous pods exhibited greater reductions in PY than membranous pods relative to their controls. These results suggest that digestive processes, coupled with environmental conditions after excretion, accelerate dormancy break, highlighting a complex interaction between biological and ecological factors in seedling regeneration. Our results provide important insights for managing pasture legumes in Mediterranean systems and highlight the need to consider herbivore‐mediated seed dispersal in restoration and sustainable agriculture.

Senesced annual legumes provide nutrients for small ruminants during summer, yet grazing pressure may significantly deplete seedbanks. We quantified seed passage and nutritional value of pods from 15 modern pasture legume cultivars fed to sheep in metabolism crates. Seed passage ranged from 8% (serradella, Ornithopus spp.) to 87% (biserrula, Biserrula pelecinus ), with significant differences observed between species and among accessions within species. To extend the analysis, we incorporated 38 data points from historical studies, revealing that seed passage was best predicted by an exponential regression model incorporating individual seed mass and hardseededness. Seed passage declined sharply with increasing seed mass; a 0.3 mg increase corresponded to a 25% reduction in passage. In clovers ( Trifolium spp.), hardseededness and seed mass were strong predictors of seed passage, explaining 64% and 58% of the variation. In contrast, seed mass accounted for 27% of variation in passage of medics ( Medicago spp.). Dry matter digestibility of pods (51%–63%) and seeds (75%–90%) varied, as did crude protein content. If a sheep consumed 1 kg of pods, the ME apparently digested from 0.3 to 6.9 MJ, while energy lost via seed passage was 0.3 to 2.7 MJ. Bladder clover ( Trifolium spumosum ) appears well‐adapted to endozoochory, producing large quantities of small, hard seeds (42% passage) that are embedded in senesced pod material that is nutritionally rich and easily prehended. Agronomists can improve persistence and summer feeding value of aerial seeded legumes by selecting for traits associated with feeding value and seed passage.

This review presents a new model for a multidisciplinary approach to development of modern forage cultivars to enable high-value meat and wool production in the mixed farming zones of Australia. Many pasture improvement activities focus on biomass production, filling novel agro-ecological niches, fixing nitrogen and phenotypic markers. Key traits that drive profitability of livestock, such as feeding value (FV), and nutritive value (NV), are rarely considered in a timely manner. Farmers are often not seriously engaged until late in the development pipeline. Of the nearly 10 000 publications that reference forage improvement or breeding and Australia, less than 5% also reference ruminant production factors such as FV, metabolisable energy, digestibility, methane or toxicity in the abstract, title or keywords. We make the case that the late engagement of livestock science and farmers results in early discarding of potentially valuable genetic material. This in turn may contribute to market and nutritional limitations that contribute to the high failure rate of new pasture cultivars. Four case studies demonstrated the within and among species variation in FV and NV. The first showed the variability in dry matter digestibility and crude protein of 20 species of herbaceous perennials at different stages of maturity. A second study with annual legumes, grasses and brassicas indicated highly significant differences in the rate of decline of NV over time and across species. The third case study focused on commercial and experimental accessions of lucerne and demonstrated highly significant differences among accessions in NV, with a doubling of livestock growth expected with the lowest and highest NV accessions. These case studies demonstrated the potential risks associated with evaluation of FV and NV after most of the germplasm has been excluded. The final case study described a different model that was used in the identification and commercialisation of a woody perennial species. This process incorporated a multidisciplinary team, farmers and livestock-relevant characteristics from the start. In 9 years, Anameka™ oldman saltbush was selected for higher palatability, 20% higher organic-matter digestibility and eight times more biomass than the average of the original genetic material.

Shade and shelter may provide protection from cold and heat stress, a source of feed during prolonged or seasonal drought, specific essential nutrients, increased pasture and crop production and improved landscape health. Cold stress contributes to the average of 8% (single) and 24% (twin) of lambs that die within 3 days of birth in Australia and the estimated 0.7% of the Australian flock that die post-shearing during extreme or unseasonal weather. Shelter has resulted in an average reduction in mortality of 17.5% for twin-born lambs and 7% for single-born lambs according to Australian studies and decreases the susceptibility of ewes to metabolic disease and possibly dystocia. Because many of the published studies are from research areas where cold stress is expected, they are not indicative of industry-wide responses, a research priority is to determine the probability of lamb and ewe deaths from cold stress across different sheep production areas. Although shelter may improve lamb survival, ewes do not always choose to lamb in a sheltered location. For this reason, there is a requirement for research into the voluntary use of shelter in commercial-sized paddocks and the role that nutritive value of shelter plays in attracting and holding ewes to shelter, and to their lambs. Heat stress may also result in lamb deaths and influences feed conversion efficiency, appetite, reproduction, wool growth and disease susceptibility. The consequences of heat stress may go unnoticed over a yearly production cycle, although there is some evidence that shade may increase weaning rates and feed intake of grazing sheep. There are ancillary benefits from shade and shelter. Trees may improve crop production through reducing wind damage and evapotranspiration and provide timber. Shrubs provide feed during the summer–autumn feed gap or drought, are useful for the management of land degradation and provide habitat for native fauna. It is clear that shade and shelter in the correct locations provide a range of benefits to livestock and the landscape; nevertheless, adoption appears low. Research that focuses on defining the benefits on a farm or landscape scale is required to support extension programs.

Context: An accession of the annual legume Trigonella balansae Boiss. & Reuter. has been selected for commercial release in Australia. Aims: As part of a duty-of-care assessment, we tested the hypothesis that sheep grazing the trigonella accession will have liveweight, condition scores and wool production similar to those of sheep grazing two widely adopted annual legumes, subterranean clover (subclover, Trifolium subterraneum L. cv. Dalkeith) and French serradella (Ornithopus sativus Brot. cv. Erica). We also hypothesised that sheep grazing the three legumes will have similar meat quality and health, as indicated by blood plasma panel analysis. Methods: Wethers (n = 6) grazed plots (n = 4) of three pasture species. Liveweight, condition scores and wool growth were measured, and a subset of animals were subject to blood sampling to assess health. Consumer sensory taste analysis was used to assess meat eating quality from two sheep per plot. Forage biomass, dry-matter digestibility, crude protein, fibre, mineral content and isoflavones were measured across the plant’s lifecycle. Key results: There were no significant differences in liveweight, wool growth, wool yield or condition score that were associated with pasture species during the grazing period. There were differences in dry-matter digestibility, minerals and crude protein content of the pastures over time. As trigonella matured, it did not meet the minimum sulfur, phosphorus, manganese, molybdenum and copper requirements for mature sheep. We found some differences in indications of animal health; however, there were no significant systematic detrimental differences between sheep grazing trigonella and the other two species. In total, 2 of 24 individual sheep grazing trigonella had more than two plasma indicators of liver damage. There were no differences in meat tenderness, juiciness, flavour and overall consumer acceptability. Conclusions: The data supported the hypotheses. Under the conditions of this experiment, the pasture legumes had the same relative feeding value. Some care must be taken in interpreting the outcome as the trigonellacomprised only 18% of the dry matter on offer at the termination of grazing. Implications: Results of this study will be considered during the commercialisation process for T. balansae.

Managed plantations of saltbush have the potential to increase the productivity and climate resilience of the farming systems of the low rainfall areas of the world, where livestock are important. The objective was to dynamically simulate the behaviour of grazing saltbush plantations with a new modelling capacity in the APSIM framework to enable the dynamic grazing of forage systems. Scenarios simulated included: the choice of plant species growing in the interrow area between shrub-rows, density of saltbush spatial arrangement, locations with different climates and soils, and grazing strategy by sheep. Comparisons of scenarios across systems were insightful during rainfall years when the shrub systems are of high value (i.e., driest/lowest 20% rainfall years in the simulation period). Overall, the efficient grazing of shrubs by dry sheep with little supplementary feeding, required the availability of a large amount of low quality interrow. Shrub plantations with an interrow of standing oats required least supplementation. Summer grazing was the optimal time for grazing shrub plantations in low rainfall years. Plantations with more shrubs relative to interrow increased the need for supplementary feeding but reduced the variation between years. This is one of the first uses of systems modelling to explore forage shrub system designs that maximise the grazing value of shrub plus interrow.

In the rain‐fed mixed‐farming systems of southern Australia, the consistent supply of high‐value forage is limited by a range of climatic, edaphic and systems constraints. Over 2 years, we compared biomass production and nutritional value of 30 accessions of perennial legumes, and predicted intake, grazing days and growth of ewes and lambs. There was significant variation in nutritional value and biomass production between and within species. Lucerne (Medicago sativa) and sulla (Hedysarum coronarium) produced the greatest amount of biomass and energy. There was variability among accessions in digestibility (DMD), acid detergent fibre (ADF) and crude protein, and the rate of change in these traits as plants matured. Trifolium species had the highest DMD across all growth stages. Hairy canary clover (Dorycnium hirsutum), erect canary clover (Dorycnium rectum), greater birdsfoot trefoil (Lotus uliginosus), Australian trefoil (Lotus australis) and running postman (Kennedia prostrata) had energy levels that would not maintain liveweight of mature sheep. In the second year, species differed in response to harvesting treatments. Lucerne and sainfoin (Onobrychis viciifolia) were more productive under a frequent cutting regime. Accessions of white clover (Trifolium repens), red clover (Trifolium pratense), alsike clover (Trifolium hybridum), cullen (Cullen australasicum), strawberry clover (Trifolium fragiferum), sainfoin and birdsfoot trefoil (Lotus corniculatus) showed some promise, while Tedera (Bituminaria bituminosa) and milkvetch (Astragalus cicer) performed poorly under the experimental conditions. We conclude by discussing additional agronomic and nutritional factors that need consideration when developing novel perennial legumes for mixed‐farming systems in the context of a changing climate.